JP5900689B2 - Optical measurement method of eyeball - Google Patents

Description

  The present invention relates to an eyeball optical measurement device and an eyeball optical measurement method.

  In Patent Document 1, a light source device that irradiates light to an eyeball that is arranged in advance at a predetermined position, and a boundary surface between the cornea and air of the eyeball that is irradiated with light emitted from the light source device Based on the intensity of the backscattered light and the intensity of the second backscattered light by the interface between the cornea and the anterior chamber, respectively, and the intensity of the first and second backscattered light, Refractive index calculating means for obtaining the refractive index of the aqueous humor that fills the anterior chamber, a storage unit that stores in advance the correspondence between the refractive index of the aqueous humor and the glucose concentration in the aqueous humor, and the storage unit Glucose concentration calculating means for determining the glucose concentration in the aqueous humor based on the correspondence stored in the above and the refractive index of the aqueous humor determined by the refractive index calculating means A concentration measuring device is described.

In Patent Document 2, an optical rotation angle of urine whose optical rotation angle range expressed by an interfering optical rotation substance other than an optical rotation optical substance with an unknown concentration is measured, and the concentration C [kg / dl] of the optical rotation substance is expressed as ( A−A _h ) / (α × L) ≦ C ≦ (A−A _l ) / (α × L)
However, A: Rotational angle of measured urine [deg]
A _h : Maximum value of optical rotation angle [deg] expressed by interfering optical rotatory substance
A _l : Minimum value of optical rotation [deg] expressed by interfering optical rotatory substances [deg]
α: Specific rotation of optically active substance [deg / cm · dl / kg]
L: Measurement optical path length [cm]
A urine test method for determining that the range is in the range is described.

Japanese Patent No. 3543923 JP 09-138231 A

When the light emitting means and the light receiving means are arranged on the eye side and the eye corner side of the eyeball, and the light crossing the anterior chamber is emitted and received, do not shift the position of the eyeball in the depth direction between the eye side and the eye corner side. When trying to emit and receive light, the skin on the front side of the eyes became an obstacle, making it difficult to arrange the light emitting means or the light receiving means.
The present invention emits light crossing the anterior chamber of the eyeball and receives light emitted from the eyeball across the anterior chamber without shifting the position of the eyeball in the depth direction between the eye side and the eye corner side. Provided is an optical measurement device for an eyeball in which the arrangement of light emitting means or light receiving means is easier than in the case of emitting and receiving light.

The invention according to claim 1 is a step of positioning the light emitting means provided on the outer corner side of the eyeball of the measurement subject on the back side with respect to the eyeball than the light receiving means provided on the eyeball side of the eyeball; Passing the light across the anterior chamber of the eyeball from the light emitting means in a state in which the eyeball is rotated, and receiving the light across the anterior chamber with the light receiving means. Is an optical measurement method for an eyeball including
The invention according to claim 2 is a step of positioning the light receiving means provided on the outer corner side of the eyeball of the measurement subject on the back side with respect to the eyeball than the light emitting means provided on the eyeball side of the eyeball; Passing the light across the anterior chamber of the eyeball from the light emitting means in a state in which the eyeball is rotated, and receiving the light across the anterior chamber with the light receiving means. Is an optical measurement method for an eyeball including
The invention according to claim 3 is characterized in that in the positioning step, positioning is performed so that at least one of the light emitting means and the light receiving means is disposed outside a region where the eyeball is exposed. Item 3. The eyeball optical measurement method according to Item 1 or 2.
According to a fourth aspect of the present invention, in the positioning step, the positioning is performed so that both the light emitting means and the light receiving means are disposed outside the exposed region of the eyeball. 3. The optical measurement method for an eyeball according to 1 or 2.

According to the invention of claim 1, 2, without offset position relative to the depth direction of the eye at the inner corner side and outer corners side compared with the case in which the emission and reception of light, is easily disposed in the light emitting means or light receiving means Become.
According to the invention of claim 3, the contact with the eyeball is suppressed as compared with the case where the light emitting means and the light receiving means are arranged in the exposed region of the eyeball.
According to the fourth aspect of the present invention, contact with the eyeball is further suppressed as compared with the case where at least one of the light emitting means and the light receiving means is disposed in the exposed area of the eyeball.

It is a figure which shows an example of a structure of the optical measuring device with which this Embodiment is applied. It is a figure explaining the method to measure the rotation angle (optical rotation) of the polarization plane by the optically active substance contained in the aqueous humor in the anterior chamber with the optical measurement device. It is a figure explaining the outline | summary of an eyeball. (A) is a vertical sectional view of the eyeball, and (b) shows a coordinate system for the eyeball. It is a figure explaining the relationship between an eyeball and an optical path. (A) is the figure which looked at the eyeball from the front, (b) is the figure which shows the optical path when the eyeball is facing the front, (c) is the figure which shows the optical path when the eyeball is abducted is there. It is a figure explaining an example of the method of installing a holding | maintenance part with respect to a face. It is a flowchart explaining the optical measurement method which measures the density | concentration of the optically active substance contained in the aqueous humor in an anterior chamber by an optical measurement apparatus, and the light irradiation and light reception method to an eyeball.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
(Optical measurement device 1)
FIG. 1 is a diagram illustrating an example of a configuration of an optical measurement device 1 to which the exemplary embodiment is applied.
The optical measuring device 1 includes an optical system 20 used for measuring characteristics of aqueous humor in the anterior chamber 13 of the eyeball 10 of the measurement subject, a control unit 40 that controls the optical system 20, an optical system 20, and a control unit 40. The holding part 50 as an example of the holding means to hold | maintain and the calculation part 60 which calculates the characteristic of aqueous humor based on the data measured using the optical system 20 are provided.
Note that the eyeball 10 shown in FIG. 1 is the left eye.

  In the following, in the optical measurement device 1 shown in FIG. 1, the direction of the upper side and the lower side of the paper surface may be referred to as the vertical direction. Moreover, the direction of the front side and the rear side of the measurement subject may be referred to as the front-rear direction. In addition, the direction from the inside (the eye side, the nose side) and the outside (the eye corner side, the ear side) as viewed from the measurement subject may be referred to as the inside / outside direction.

The characteristics of the aqueous humor measured by the optical measurement device 1 include the rotation angle of the polarization plane of linearly polarized light (optical rotation α _M ) and the color absorption (circular dichroism) of circularly polarized light. Say. Here, the polarization plane of linearly polarized light refers to a plane in which a magnetic field vibrates in linearly polarized light.

  The anterior chamber 13 in the eyeball 10 is a region between a crystalline lens 12 (see FIG. 3 to be described later) and a cornea 14 (see FIG. 3) serving as a lens, and is filled with aqueous humor. The anterior chamber 13 is circular when viewed from the front. The eyeball 10 is almost a sphere, but the anterior chamber 13 protrudes slightly from the surface of the sphere. FIG. 1 shows a state where the eyelid 17 is opened.

The optical system 20 includes a light emitting unit 21, a polarizer 22, a first mirror 23, a second mirror 24, a compensator 25, an analyzer 26, and a light receiving unit 27.
The light emitting unit 21 may be a light source having a wide wavelength width such as a light emitting diode (LED) or a lamp, or may be a light source having a narrow wavelength width such as a laser. In addition, the one where a wavelength width is narrow is preferable.
Further, it may emit light having at least two wavelengths.

  The polarizer 22 is, for example, a Nicol prism or the like, and allows linearly polarized light having a predetermined polarization plane to pass through from incident light.

  It is preferable that the first mirror 23 and the second mirror 24 bend the optical path 28 and maintain linearly polarized light as it is before and after reflection. What disturbs the state of polarization, such as rotating the polarization plane or changing the linearly polarized light into elliptically polarized light, is not preferable. If the optical path 28 does not need to be bent, the first mirror 23 and / or the second mirror 24 may not be provided.

  The compensator 25 is a magneto-optical element such as a Faraday element using a garnet, for example, and rotates the polarization plane of linearly polarized light by a magnetic field.

The analyzer 26 is the same member as the polarizer 22 and allows linearly polarized light having a predetermined polarization plane to pass therethrough.
The light receiving unit 27 is a light receiving element such as a silicon diode, and outputs an output signal corresponding to the intensity of light.

  In addition, you may provide the display part (not shown) which displays the characteristic (concentration of an optically active substance, etc.) of the aqueous humor calculated by the calculation part 60 after measurement.

  The control unit 40 controls the light emitting unit 21, the compensator 25, the light receiving unit 27, and the like in the optical system 20 to obtain measurement data relating to the characteristics of aqueous humor. In addition, the measurement data is transmitted to the calculation unit 60.

The holding unit 50 holds the optical system 20 and the control unit 40, and the optical path 28 set in the optical system 20 is positioned in a state where the end is in contact with a predetermined position around the eyeball 10. The optical system 20 is held so as to pass through the aqueous humor in the anterior chamber 13. As a method of bringing the holding unit 50 into contact with the periphery of the eyeball 10, the person to be measured or another person may hold the optical measurement device 1 with his / her hand to make contact, or the optical measurement device 1 automatically moves back and forth. Alternatively, a driving device that drives the motor may be used. Further, as long as the holding unit 50 can be positioned with respect to the eyeball 10, the contact area does not need to be around the eyeball 10, and may be another area of the face of the person to be measured. If positioning is possible without making contact, it is not necessary to make contact.
As will be described later, when the eyeball 10 is rotated (extraversion described later), the light path 28 indicated by a broken line passes through the anterior chamber 13 so that the light emitted from the light emitting unit 21 passes through the light receiving unit. 27 may be set to receive light.
Further, the passage of light across the anterior chamber 13 means that when the eyeball 10 is viewed from the front, an angle closer to the inner and outer directions than the vertical direction (that is, less than ± 45 ° with respect to the horizontal axis in the inner and outer directions). (Including the case of passing diagonally in the front-rear direction).

  And the holding | maintenance part 50 may be equipped with the eyepiece member 51 which fixed the optical measuring device 1 with respect to the eyeball 10, and was processed so that the optical path 28 might not shift | deviate.

  The holding unit 50 shown in FIG. 1 has a shape obtained by cutting a cylinder along a plane parallel to the axial direction. However, this is to make the optical system 20 easier to see, and may be a cylinder. Further, the cross section may be a cylinder such as an ellipse or a quadrilateral. Further, as in FIG. 1, a shape in which a part of the cylindrical shape is cut off may be used.

  Note that the holding unit 50 may be a frame of glasses. That is, the optical measurement device 1 may be a glasses type in which the optical system 20 and the control unit 40 are provided in glasses.

  The calculation unit 60 receives the measurement data from the control unit 40 and calculates the characteristics of the aqueous humor.

Here, the light emitted from the light emitting unit 21 travels along the optical path 28 and enters the light receiving unit 27. That is, the light emitted from the light emitting unit 21 toward the eyeball 10 side passes through the polarizer 22 and is bent by the first mirror 23 in a direction crossing the anterior chamber 13 (a direction parallel to the eyes). And it passes in the direction which crosses the anterior chamber 13. Further, the second mirror 24 is bent in a direction away from the eyes. Then, the light passes through the compensator 25 and the analyzer 26 and enters the light receiving unit 27.
In FIG. 1, a portion including the light emitting unit 21, the polarizer 22, and the first mirror 23 is a light emitting system 20A, which is an example of a light emitting unit. A portion including the second mirror 24, the compensator 25, the analyzer 26, and the light receiving unit 27 is a light receiving system 20B, which is an example of a light receiving unit.
As will be described later, the holding unit 50 holds the light emitting system 20A in a state shifted to the rear side (back side) as compared to the light receiving system 20B, that is, asymmetrical.
The light emitting system 20A and the light receiving system 20B may be replaced with each other.

Here, an example will be described in which the optical measuring device 1 measures the aqueous humor in the anterior chamber 13 and is used for calculating the glucose concentration.
In diabetic patients, the amount of insulin administered is controlled by the glucose concentration in the blood. Therefore, a diabetic patient is required to always grasp the glucose concentration in blood. And the measurement of the glucose concentration in blood is mainly performed by a method of puncturing a fingertip or the like with an injection needle and collecting a very small amount of blood. However, even a trace amount of blood is accompanied by pain due to pain at the time of blood collection. Thus, there is a growing demand for non-invasive testing methods that replace invasive testing methods such as puncture.
The aqueous humor in the anterior chamber 13 which is almost the same component as serum contains protein, glucose, ascorbic acid and the like. It is known that there is a correlation between the glucose concentration in blood and the glucose concentration in aqueous humor. Further, in the aqueous humor, there is no cellular material in the blood, and the influence of light scattering is small. Proteins, glucose, ascorbic acid and the like contained in aqueous humor are optically active substances and have optical activity. That is, the aqueous humor is advantageous as a site for optically measuring the concentration of glucose or the like using optical rotation.

In the method of optically obtaining the concentration of the optically active substance contained in the aqueous humor, the optical paths that can be set are the following two.
On the other hand, light is incident on the eyeball 10 at an angle close to vertical, and at the interface between the cornea 14 (see FIG. 3 to be described later) and the aqueous humor or between the aqueous humor and the crystalline lens 12 (see FIG. 3). An optical path that reflects light and receives (detects) the reflected light. The other is an optical path through which light is incident on the eyeball 10 at an angle close to parallel and receives (detects) light that has passed through the aqueous humor in the anterior chamber 13.

First, there is a possibility that light reaches the retina 16 (see FIG. 3) through an optical path through which light is incident on the eyeball 10 at an angle close to vertical. In particular, when a highly coherent laser is used for the light emitting unit 21, it is not preferable that light reaches the retina 16.
On the other hand, in the optical path in which light is incident at an angle close to parallel to the eyeball 10, the light passes through the cornea 14 so as to cross the anterior chamber 13 and the light that has passed through the aqueous humor is received (detected). . For this reason, it is suppressed that light reaches the retina 16.

However, the eyeball 10 has a substantially spherical shape, and a nose (nasal bridge) is positioned on either the light incident side or the light receiving side, and the light emission in the optical system 20 is influenced by the influence. The space where the unit 21, the polarizer 22, the compensator 25, the analyzer 26, the light receiving unit 27 and the like are arranged is narrow.
Therefore, in order to set the optical path 28 so that light is incident on the eyeball 10 at an angle close to parallel and passes through the anterior chamber 13, as shown in FIG. By providing the mirror 24 and bending the optical path 28, the space is effectively used.
If the optical system 20 is small, it is not necessary to bend the optical path 28.

FIG. 2 is a diagram for explaining a method of measuring the rotation angle (optical rotation) of the polarization plane by the optically active substance contained in the aqueous humor in the anterior chamber 13 by the optical measurement device 1. Here, for ease of explanation, the description of the first mirror 23 and the second mirror 24 is omitted assuming that the optical path 28 is not bent (is a straight line).
In the optical system 20 shown in FIG. 2, the state of polarization viewed from the traveling direction of light between the light emitting unit 21, the polarizer 22, the anterior chamber 13, the compensator 25, the analyzer 26, and the light receiving unit 27. Is indicated by an arrow in the circle.

The light emitting unit 21 emits light having a random polarization plane. Then, the polarizer 22 passes linearly polarized light having a predetermined polarization plane. In FIG. 2, as an example, it is assumed that linearly polarized light having a polarization plane parallel to the paper surface passes.
The plane of polarization of the linearly polarized light that has passed through the polarizer 22 is rotated by the optically active substance contained in the aqueous humor in the anterior chamber 13. In FIG. 2, it is assumed that the polarization plane rotates by an angle α _M (optical rotation α _M ).

Next, by applying a magnetic field to the compensator 25, the polarization plane rotated by the optically active substance contained in the aqueous humor in the anterior chamber 13 is restored.
Then, the linearly polarized light that has passed through the analyzer 26 is received by the light receiving unit 27 and converted into an output signal corresponding to the intensity of the light.

Here, an example of a method for measuring the optical rotation α _M by the optical system 20 will be described.
First, in a state where the light emitted from the light emitting unit 21 does not pass through the anterior chamber 13, in the optical system 20 including the light emitting unit 21, the polarizer 22, the compensator 25, the analyzer 26, and the light receiving unit 27, The compensator 25 and the analyzer 26 are set so that the output signal is minimized. As shown in FIG. 2, in a state where light does not pass through the anterior chamber 13, the polarization plane of linearly polarized light that has passed through the polarizer 22 is orthogonal to the polarization plane that passes through the analyzer 26.
In FIG. 2, the polarization plane of the polarizer 22 and the polarization plane before passing through the analyzer 26 are both parallel to the paper surface. However, when the plane of polarization is rotated in advance by the compensator 25, the plane of polarization before passing through the analyzer 26 may be tilted from a plane parallel to the paper surface. That is, the compensator 25 and the analyzer 26 may be set so that the output signal of the light receiving unit 27 is minimized when light does not pass through the aqueous humor in the anterior chamber 13.

Next, it is assumed that light passes through the anterior chamber 13. Then, the polarization plane is rotated by the optically active substance contained in the aqueous humor of the anterior chamber 13. For this reason, the output signal from the light receiving unit 27 deviates from the minimum value. Therefore, the magnetic field applied to the compensator 25 is set so that the output signal from the light receiving unit 27 is minimized. That is, the plane of polarization is rotated by the compensator 25 and is orthogonal to the plane of polarization passing through the analyzer 26.
At this time, the angle of the polarization plane rotated by the compensator 25 corresponds to the optical rotation α _M generated by the optically active substance contained in the aqueous humor. Since the relationship between the magnitude of the magnetic field applied to the compensator 25 and the angle of the rotated polarization plane is known in advance, the optical rotation α _M can be determined from the magnitude of the magnetic field applied to the compensator 25.
Although described an example using compensator 25 as a method for determining the optical rotation alpha _M, may be obtained optical rotation alpha _M outside compensator 25. 1 and 2 show the orthogonal polarizer method (which uses the compensator 25), which is the most basic measurement method for measuring the rotation angle (optical rotation α _M ) of the polarization plane. Other measurement methods such as a photon method, a Faraday modulation method, and an optical delay modulation method may be applied.

More specifically, light having a plurality of wavelengths λ (wavelengths λ ₁ , λ ₂ , λ ₃ ,...) Is incident on the aqueous humor in the anterior chamber 13 from the light emitting unit 21, and the optical rotation α _{M is applied to} each. (Optical rotations α _M1 , α _M2 , α _M3 ,...) Are obtained. A set of the wavelength λ and the optical rotation α _M is taken into the calculation unit 60, and the concentration of the optically active substance to be obtained is calculated.

The aqueous humor contains a plurality of optically active substances as described above. Therefore, the measured optical rotation α _M is the sum of the optical rotation α by each of the plurality of optically active substances. Therefore, it is necessary to calculate the concentration of the optically active substance to be obtained from the measured optical rotation α _M.
The calculation of the concentration of the optically active substance to be obtained may be performed by using a known method as disclosed in, for example, Japanese Patent Application Laid-Open No. 09-138231 (Patent Document 2), and the description thereof is omitted.

FIG. 3 is a diagram for explaining the outline of the eyeball 10. 3A is a cross-sectional view of the eyeball 10 in the vertical direction, and FIG. 3B shows a coordinate system for the eyeball 10.
As shown in FIG. 3A, the eyeball 10 has a substantially spherical outer shape, and has a glass body 11 in the center. A crystalline lens 12 serving as a lens is embedded in a part of the glass body 11. There is an anterior chamber 13 outside the lens 12, and a cornea 14 outside. The peripheral portion of the crystalline lens 12 is surrounded by an iris, and the center is the pupil 15. The glass body 11 is covered with a retina 16 except for a portion in contact with the crystalline lens 12.
That is, the anterior chamber 13 is a region surrounded by the cornea 14 and the crystalline lens 12 and protrudes from the spherical shape of the eyeball 10 in a convex shape. The anterior chamber 13 is filled with aqueous humor.

It is assumed that the eyeball 10 shown in FIG. 3B is the left eye and faces the front. That is, the left side is the eye side (nose side), and the right side is the corner of the eye (ear side). Then, through the center O (rotation point) of the rotational movement performed by the eyeball 10, the axis pointing from right to left is the X axis, the axis from the back to the front is the Y axis, and the axis from the bottom to the top is the Z axis. And
Here, rotation of the eyeball 10 toward the eye (nose side) around the Z axis is referred to as “inversion”, and rotation to the corner of the eye (ear side) is referred to as “abduction”. In the right eye, the directions of rotation about the Z axis, that is, the directions of “inner rotation” and “external rotation” are reversed.
Incidentally, rotating the eyeball 10 upward about the X axis is referred to as “upward”, rotating downward is referred to as “downward”, and rotating about the Y axis is referred to as “rotation”.
Here, “abduction” means a state in which the eyeball 10 (pupil 15) faces upward, as well as a case where the eyeball 10 (pupil 15) faces upward, in addition to the case where the eyeball 10 (pupil 15) turns frontward. For example, in a state where it is oriented within the range of + 45 ° in the Z-axis direction, when rotating to the outer corner of the eye (ear side), or in a state where the eyeball 10 (pupil 15) is directed downward, for example, −45 ° in the Z-axis direction. This includes the case of rotating to the outer corner of the eye (ear side) in the state of facing within the range.
The same applies to “inner rotation”.

  FIG. 4 is a diagram for explaining the relationship between the eyeball 10 and the optical path 28. 4A is a diagram of the eyeball 10 viewed from the front, FIG. 4B is a diagram illustrating the optical path 28 when the eyeball 10 is facing the front, and FIG. It is a figure which shows the optical path 28 in the case of rotating. FIG. 4B and FIG. 4C show a state in which a person is viewed from the head side (upper side). These were drawn by simulation modeling the face.

As shown in FIG. 4A, the optical path 28 is set so as to be directed from the corner of the eye (ear side) to the side of the eye (nose side). This is for ease of explanation. The optical path 28 may be set so as to go from the eye side (nose side) to the corner of the eye (ear side).
As shown in FIG. 4B, when the eyeball 10 faces the front, the light emitted from the light emitting system 20A (see FIG. 1) passes through the cornea 14 and enters the anterior chamber 13. Since the refractive index of the aqueous humor in the cornea 14 and the anterior chamber 13 is larger than air, and the anterior chamber 13 and the cornea 14 are convex, the optical path 28 is bent toward the eyeball 10 side. Even after passing through the anterior chamber 13, the optical path 28 is further bent toward the eyeball 10. Therefore, the optical path 28 after passing through the anterior chamber 13 follows a locus approaching the face surface.
In a general person, the skin F1 on the eye side protrudes in front of the skin F2 on the eye corner side, and there is also a nose on the eye side. Therefore, when the eyeball 10 faces the front, In some cases, it is difficult to secure a space for arranging the light receiving system 20B (see FIG. 1) on the side.
If the light receiving system 20B can be disposed at a position very close to the eyeball 10 such as a position close to the white eye portion (white eye portion) I in the region R where the eyeball 10 is exposed from the skin F1 and the skin F2, The presence of the skin F1 and the nose on the eye side can be ignored. However, the members constituting the light receiving system 20B easily come into contact with the eyeball 10.

On the other hand, as shown in FIG. 4C, when the eyeball 10 is abducted, that is, when the line of sight is directed to the outer corner of the eye (ear side), the light emitted from the light emitting system 20A is It passes through the cornea 14 and enters the anterior chamber 13. At this time, since the eyeball 10 is abducted, the optical path 28 after passing through the anterior chamber 13 follows a path farther from the face surface than in the case of FIG.
By rotating the eyeball 10, the space on the eye side is widened, and the light receiving system 20 </ b> B can be easily placed on the eye side as compared with the case where the eyeball 10 is facing the front as shown in FIG. In other words, the light receiving system 20B may be arranged on the skin F1 on the temporal side between the region R where the eyeball 10 is exposed and the nose, utilizing the widened space on the temporal side. In this case, since the distance between the members constituting the light receiving system 20B and the eyeball 10 is increased, the members constituting the light receiving system 20B are suppressed from contacting the eyeball 10.
Further, even when the light receiving system 20B is arranged on the exposed white-eye portion I ′ of the eyeball 10, the white-eye portion I ′ is the white-eye portion I when the eyeball 10 in FIG. In comparison, the optical path 28 is separated from the eyeball 10 as it becomes wider. Therefore, if the light receiving system 20B is disposed at a position away from the eyeball 10, the members constituting the light receiving system 20B are prevented from coming into contact with the eyeball 10.

  On the other hand, on the eye corner side, the space becomes narrower by rotating the eyeball 10 than in the case where the eyeball 10 shown in FIG. However, since the space on the outer corner of the eye is originally easier to secure than the outer side of the eye, the light emitting system 20A may be disposed on the exposed white-eye portion II ′, the skin F2 on the outer corner of the eye, or on the outer side.

  In order to prevent the members of the light emitting system 20A and the members of the light receiving system 20B from coming into contact with the exposed eyeball 10, the light emitting system 20A or / and / or within the region R where the eyeball 10 is exposed on both the eyeball side and the eyeball side. The light receiving system 20B may not be disposed, and the light emitting system 20A and / or the light receiving system 20B may be disposed outside the range of the region R where the eyeball is exposed, for example, on the skin F1 or the skin F2. In this way, even when the position is shifted in the front-rear direction, the contact of the member with the eyeball 10 is suppressed. It should be noted that the light emitting system 20A and / or the light receiving system 20B may be disposed outside the range of the region R where the eyeball 10 is exposed on at least one of the eye side or the eye corner side.

The case where the optical path 28 is set so as to go from the outer corner of the eye (ear side) to the front of the eye (nose side) has been described above. The same applies to the case where the optical path 28 is set so as to go from the eye side (nose side) to the eye corner side (ear side). That is, in the above, the light emitting system 20A may be read as the light receiving system 20B, and the light receiving system 20B may be read as the light emitting system 20A.
In the present embodiment, “on skin F1” and “on skin F2” include both a state where the skin is in contact and a state where the skin is not in contact. This refers to the position that overlaps the skin when viewed from above.

If the optical path 28 deviates from the anterior chamber 13, accurate measurement may not be performed. Therefore, more accurate measurement is performed by setting the optical path 28 so that the light passes through the anterior chamber 13 without deviating from the anterior chamber 13. The optical rotation α _M is affected by the optical path length, which is the length of light passing through the aqueous humor in the anterior chamber 13. Therefore, when the optical path 28 is short, actually for relative variations of the optical path length to be used for light to calculate the optical path length and optical rotation alpha _M passing through tends to increase, and when the optical path 28 is long compared As a result, the accuracy of measurement tends to deteriorate.
In the present embodiment, since the optical path 28 is set so as to cross the anterior chamber 13, the optical path length is set to be longer than in the case where light is incident on the eyeball 10 at an angle close to vertical. Thereby, compared with the case where light is incident at an angle close to vertical, it is easy to improve the measurement accuracy.

FIG. 5 is a diagram illustrating an example of a method of installing the holding unit 50 on the face.
As described with reference to FIG. 4, in a general person, the skin F <b> 1 on the eye side protrudes in front of the skin F <b> 2 on the eye corner side. For this reason, the holding | maintenance part 50 is provided so that the shape (unevenness | corrugation) of the skin F1 of the face side of the face, and the skin F2 of the outer corner of the face may be provided. That is, the corner part 50B in contact with the skin F2 on the corner of the corner of the eye is shifted to the rear side (back side) as compared to the end part 50A on the corner side of the holding part 50 in contact with the skin F1 on the corner side. In other words, the holding | maintenance part 50 is comprised asymmetrically by the eye side and the eye corner side. Similarly, the light emitting system 20 </ b> A and the light receiving system 20 </ b> B held by the holding unit 50 are arranged on the front side with respect to the front-rear direction of the eyeball 10 and on the front of the eyeball side with respect to the front-rear direction of the eyeball 10. They are shifted from each other so as to be rearward with respect to the direction.

(Optical measurement method and light irradiation and light reception method to the eyeball)
FIG. 6 is a flowchart for explaining an optical measurement method for measuring the concentration of an optically active substance contained in aqueous humor in the anterior chamber 13 by the optical measurement device 1 and a method for irradiating and receiving light to the eyeball 10.
First, the person to be measured turns on the optical measuring device 1 and wears the optical measuring device 1 (denoted as S11 in step 11 and FIG. 6; the same applies hereinafter). When the optical measurement device 1 is turned on, the optical system 20, the control unit 40, and the calculation unit 60 are in an operating state.
Next, it is determined by the control unit 40 whether or not the person to be measured has completed mounting (mounting completion) of the optical measuring device 1 (step 12). For example, a button for notifying the completion of the mounting is provided in the optical measuring device 1 so that the measurement subject presses the button for notifying the completion of the mounting after the mounting of the optical measuring device 1 is completed. Then, the control unit 40 may determine whether or not the measurement subject has completed the mounting of the optical measurement device 1 depending on whether or not the button for notifying the completion of the mounting has been pressed.
If a negative (No) determination is made in step 12, that is, if the mounting is not completed, the process returns to step 12 to wait for the mounting completion.

On the other hand, when an affirmative (Yes) determination is made, it is determined whether measurement may be started (measurement start) (step 13). For example, a button for instructing measurement start is provided in the optical measurement device 1 so that the measurement subject presses the button for instructing measurement start after the installation of the optical measurement device 1 is completed. Then, the control unit 40 may determine whether or not measurement may be started depending on whether or not a button for notifying measurement start has been pressed.
If a negative (No) determination is made in step 13, that is, if measurement is not started, the process returns to step 13 and waits for measurement start.

On the other hand, when an affirmative (Yes) determination is made, that is, when measurement start is instructed, the control unit 40 emits light from the light emitting unit 21 in the light emitting system 20A (step 14), and the anterior eye The optical rotation α _M of the light passing through the aqueous humor in the chamber 13 is measured (step 15). Next, the control unit 40 transmits measurement data such as the measured optical rotation α _M to the calculation unit 60.
Then, the calculation unit 60 calculates the concentration of the optically active substance to be obtained in the aqueous humor that is the measurement target (calculation of the concentration of the measurement target) (step 16).

In the flowchart of FIG. 6, as an example, the method of calculating the concentration of the optically active substance desired to be obtained contained in the aqueous humor has been described, but it may be configured to measure other characteristics of the aqueous humor.
In addition to the characteristics relating to aqueous humor, the configuration described in the present embodiment may be applied to obtain characteristics relating to the cornea and the like existing in the optical path 28. That is, if light from the outside of the eyeball 10 is incident and light is passed through the cornea 14 and the aqueous humor in the anterior chamber 13, the characteristics relating to the eyeball 10 are obtained. Configuration can be applied.

In the present embodiment, the left eye has been described, but the present invention may be applied to the right eye. The direction of abduction of the eyeball 10 is a direction away from the nose, and both the light emitted from the light emitting system 20A passes through the anterior chamber 13 and is received by the light receiving system 20B. The optical path 28 can be set to
Further, in the present embodiment, the holding unit 50 discloses a state in which the light emitting system 20A is shifted to the rear side (back side) compared to the light receiving system 20B, that is, an asymmetrical holding form. The present invention is not necessarily limited to such a form. A configuration in which the light emitting system 20A and the light receiving system 20B are held symmetrically may be used as long as the irradiation and reception of light crossing the anterior chamber of the eyeball 10 can be performed in a state where the eyeball 10 is abducted. An asymmetric structure other than that disclosed in the present embodiment may be used.
Furthermore, the control unit 40 and the calculation unit 60 may be integrally configured, and data transmission / reception between the control unit 40 and the calculation unit 60 may be performed by wire or wirelessly.

DESCRIPTION OF SYMBOLS 1 ... Optical measuring device, 10 ... Eyeball, 11 ... Glass body, 12 ... Lens, 13 ... Anterior chamber, 14 ... Cornea, 15 ... Pupil, 16 ... Retina, 20 ... Optical system, 20A ... Light emission system, 20B ... Light reception System 21... Light emitting unit 22. Polarizer 23. First mirror 24 24 Second mirror 25 Compensator 26 Analyzer 27 27 Light receiving unit 28 Optical path 40 Control unit 50. Holding unit, 51 ... eyepiece member, 60 ... calculating unit

Claims (4)

Positioning the light emitting means provided on the outer corner side of the eyeball of the measurement subject on the back side with respect to the eyeball rather than the light receiving means provided on the eyeball side of the eyeball;
Passing the light across the anterior chamber of the eyeball from the light emitting means in a state of rotating the eyeball;
A method of measuring light of an eyeball, comprising: receiving the light crossing the anterior chamber with the light receiving means. Positioning the light receiving means provided on the outer corner side of the eyeball of the measurement subject on the back side with respect to the eyeball than the light emitting means provided on the eyeball side of the eyeball;
Passing the light across the anterior chamber of the eyeball from the light emitting means in a state of rotating the eyeball;
A method of measuring light of an eyeball, comprising: receiving the light crossing the anterior chamber with the light receiving means. 3. The eyeball according to claim 1, wherein the positioning step includes positioning so that at least one of the light emitting unit and the light receiving unit is disposed outside a region where the eyeball is exposed. Optical measurement method. The eyeball light according to claim 1 or 2, wherein the positioning step includes positioning so that both the light emitting means and the light receiving means are disposed outside the range of the exposed area of the eyeball. Measurement method.

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